Drill rod guard and systems and methods of using same

ABSTRACT

A drill rod guard having a feed shaft assembly that supports a feed shell for receiving a drill rod. First and second shafts are respectively pivotally coupled to opposed sides of the feed shaft assembly. A plurality of guard elements are operatively coupled to the first and second shafts, and opposed guard elements are selectively engageable with one another. Upon engagement between the opposed guard elements, the guard elements cooperate with the feed shell and/or the feed shaft assembly to substantially enclose the portion of the drill rod within the feed shell to thereby prevent contact with the drill rod.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application No. 61/792,740, filed Mar. 15, 2013, which is incorporated by reference herein in its entirety.

FIELD

Implementations described herein relate generally to devices, systems and methods for guarding against contact with rotating drill rods.

BACKGROUND

Drill rigs generally include a supporting mast with a mounted drill head. The drill head can be capable of moving along the mast. Additionally, the drill head can receive and engage the upper end of a drill string. The drill head can rotate the drill string and a drill bit mounted to the drill string to drill a formation. The drill string can include a plurality of drill rods that are connected end to end.

During a typical drilling operation, when the drill head reaches the lower end of the mast, the drill string can be clamped and the drill head disconnected from the drill string. An additional length of drill rod can then be added to the end of the drill string, the drill head can be connected to the new rod, and the drilling process can be resumed once again. During a drilling operation, depending on the depth of the borehole, numerous drill rods can be added to the drill string in order to reach a desired depth.

The process of drilling often involves personnel being in close proximity to rotating drill rods. Rotating drill rods are considered to be a dangerous part of drilling equipment. Drilling personnel may be at risk of serious injury or death through becoming entangled in the rotating drill rod and being crushed against the supporting mast or adjacent structures. The risk is even higher when personnel need to manually add or remove sections of drill-string, take samples, remove spoil, or simply walk close by on uneven or slippery ground. Accidental contact with such rotating parts needs to be prevented; however, safe yet unobstructed or minimally obstructed access to the drill rod is needed to perform necessary tasks.

Accordingly, a need for protective equipment that is suitably designed and operated to allow drilling personnel to work safely and productively in proximity to rotating drill rods.

SUMMARY

It is to be understood that this summary is not an extensive overview of the disclosure. This summary is exemplary and not restrictive, and it is intended to neither identify key or critical elements of the disclosure nor delineate the scope thereof. The sole purpose of this summary is to explain and exemplify certain concepts of the disclosure as an introduction to the following complete and extensive detailed description.

Implementations described herein comprise devices, systems and methods for guarding against contact with rotating drill rods.

Described herein, in one aspect, is a drill rod guard for use with a drilling system. The drill rod guard can have a longitudinal axis. The drilling system can comprise a feed shell having first and second side portions positioned on opposing sides of the longitudinal axis of the drill rod guard. The feed shell can be configured to receive at least a portion of a drill rod. The drill rod guard can comprise a feed shaft assembly configured to support the feed shell. The feed shaft assembly can comprise at least one support element. Each support element can comprises a first side portion and a second side portion, and the first side portion can be positioned on an opposing side of the longitudinal axis of the drill rod guard from the second side portion. The first side portion of each support element can be configured to be positioned proximate the first side portion of the feed shell, and the second side portion of each support element can be configured to be positioned proximate the second side portion of the feed shell. The drill rod guard can further comprise opposed first and second shafts. The first shaft can be pivotally coupled to the first side portions of each support element of the feed shaft assembly, and the second shaft can be pivotally coupled to the second side portions of each support element of the feed shaft assembly. The first shaft can be configured for selective rotation relative to a first rotational axis and the second shaft can be configured for selective rotation relative to a second rotational axis. The first rotational axis and the second rotational axis can be substantially parallel to the longitudinal axis of the drill rod guard. The drill rod guard can further comprise a plurality of guard elements. The plurality of guard elements can comprise a first set of guard elements operatively coupled to the first shaft and a second set of guard elements operatively coupled to the second shaft. Each guard element of the first set of guard elements can be substantially opposed from and configured for selective engagement with a corresponding guard element of the second set of guard elements. Upon engagement between the first set of guard elements and the second set of guard elements, the plurality of guard elements can be configured to cooperate with the first and second side portions of the feed shell to substantially enclose the portion of the drill rod within the feed shell.

Described herein, in another aspect, is a drilling system configured for drilling relative to a drilling axis. The drilling system can comprise a drill head assembly and a drill rod operatively coupled to the drill head assembly. The drilling system can further comprise a feed shell having first and second side portions positioned on opposing sides of the drilling axis, and the feed shell can be configured to receive at least a portion of a drill rod. The drilling system can further comprise a drill rod guard. The drill rod guard can comprise a feed shaft assembly configured to support the feed shell. The feed shaft assembly can comprise at least one support element, and each support element can comprise opposed first and second side portions. The first side portion can be positioned proximate the first side portion of the feed shell and the second side portion of each support element can be positioned proximate the second side portion of the feed shell. The drill rod guard can further comprise opposed first and second shafts. The first shaft can be pivotally coupled to the first side portions of each support element of the feed shaft assembly, and the second shaft can be pivotally coupled to the second side portions of each support element of the feed shaft assembly. The first shaft can be configured for selective rotation relative to a first rotational axis, and the second shaft can be configured for selective rotation relative to a second rotational axis, wherein the first rotational axis and the second rotational axis are substantially parallel to the drilling axis. The drill rod guard can further comprise a plurality of guard elements. The plurality of guard elements can comprise a first set of guard elements operatively coupled to the first shaft and a second set of guard elements operatively coupled to the second shaft. Each guard element of the first set of guard elements can be substantially opposed from and configured for selective engagement with a corresponding guard element of the second set of guard elements. Upon engagement between the first set of guard elements and the second set of guard elements, the plurality of guard elements can be configured to cooperate with the first and second side portions of the feed shell to substantially enclose the portion of the drill rod within the feed shell.

The first and second shafts of the drill rod guard can be configured for rotation about and between a first rotational position and a second rotational position. When the first and second shafts are positioned in the first rotational position, each respective guard element can be configured for movement about and between a closed position and a partially open position. In the closed position, the guard element can be positioned for engagement with a corresponding opposed guard element. Each guard element of the plurality of guard elements can be biased toward the closed position.

The drill head assembly can be configured for selective axial movement along a length of the feed shell relative to the drilling axis. The drill head assembly can comprise a plurality of drill head components and optionally can further comprise a deflecting frame that generally defines an outer periphery of the drill head assembly and is spaced from the plurality of drill head components. Upon axial movement of the drill head assembly through the drill rod guard, the deflecting frame can be configured to contact inner surfaces of the plurality of guard elements. When the first and second shafts are positioned in the first rotational position and the drill head assembly moves through the drill rod guard relative to the drilling axis, each respective guard element can be configured for movement to the partially open position upon application of an outward radial force to the guard element by the deflecting frame of the drill head assembly and each respective guard element can be configured to return to the closed position when the outward radial force is removed upon disengagement between the deflecting frame and the guard element.

Also described herein are methods of using the disclosed drill rod guard and drilling systems.

Additional features and advantages of exemplary implementations of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of such exemplary implementations. The features and advantages of such implementations may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features will become more fully apparent from the following description and appended claims, or may be learned by the practice of such exemplary implementations as set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate aspects and together with the description, serve to explain the principles of the methods and systems.

FIG. 1 illustrates a perspective view of an exemplary drilling system as disclosed herein. As shown, the drilling system can comprise a drill rod guard with a plurality of guard elements in a closed position.

FIG. 2 illustrates a perspective view of an exemplary drill rod guard attached to a feed shaft with a plurality of guard elements in a closed position.

FIG. 3 illustrates a perspective view of an exemplary drill rod guard attached to a feed shaft with a plurality of guard elements in a fully open position.

FIG. 4 illustrates an end view of an exemplary drill rod guard attached to a feed shaft with a plurality of guard elements in a closed position.

FIG. 5A illustrates a perspective view of an outer surface of an exemplary guard element as disclosed herein. FIG. 5B illustrates a perspective view of an inner surface of an exemplary guard element as disclosed herein.

FIGS. 6A-6D are side perspective views depicting the sequential movement of a drill head assembly through a drill rod guard as disclosed herein. FIG. 6A illustrates the guard elements of the drill rod guard in a closed position prior to contact between a deflecting frame of the drill head assembly and the drill rod guard. FIG. 6B illustrates the drill head assembly positioned partially within the drill rod guard such that the guard elements in contact with the deflecting frame are positioned in a partially open position. FIG. 6C illustrates the drill head assembly positioned entirely within the drill rod guard such that the guard elements in contact with the deflecting frame are positioned in a partially open position and the guard elements that are not in contact with the deflecting frame are positioned in the closed position. FIG. 6D illustrates the drill head assembly positioned entirely within the drill rod guard but advanced beyond a portion of the guard elements such that the guard elements that are no longer in contact with the deflecting frame are returned to the closed position.

DETAILED DESCRIPTION

The present invention can be understood more readily by reference to the following detailed description, examples, drawing, and claims, and their previous and following description. However, before the present devices, systems, and/or methods are disclosed and described, it is to be understood that this invention is not limited to the specific devices, systems, and/or methods disclosed unless otherwise specified, as such can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting.

The following description of the invention is provided as an enabling teaching of the invention in its best, currently known aspect. To this end, those skilled in the relevant art will recognize and appreciate that many changes can be made to the various aspects of the invention described herein, while still obtaining the beneficial results described herein. It will also be apparent that some of the desired benefits described herein can be obtained by selecting some of the features described herein without utilizing other features. Accordingly, those who work in the art will recognize that many modifications and adaptations to the present invention are possible and can even be desirable in certain circumstances and are a part described herein. Thus, the following description is provided as illustrative of the principles described herein and not in limitation thereof.

Reference will be made to the drawings to describe various aspects of one or more implementations of the invention. It is to be understood that the drawings are diagrammatic and schematic representations of one or more implementations, and are not limiting of the present disclosure. Moreover, while various drawings are provided at a scale that is considered functional for one or more implementations, the drawings are not necessarily drawn to scale for all contemplated implementations. The drawings thus represent an exemplary scale, but no inference should be drawn from the drawings as to any required scale.

In the following description, numerous specific details are set forth in order to provide a thorough understanding described herein. It will be obvious, however, to one skilled in the art that the present disclosure may be practiced without these specific details. In other instances, well-known aspects of drilling assemblies and rotating drill rods have not been described in particular detail in order to avoid unnecessarily obscuring aspects of the disclosed implementations.

As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

“Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

Throughout the description and claims of this specification, the word “comprise” and variations of the word, such as “comprising” and “comprises,” means “including but not limited to,” and is not intended to exclude, for example, other additives, components, integers or steps. “Exemplary” means “an example of” and is not intended to convey an indication of a preferred or ideal aspect. “Such as” is not used in a restrictive sense, but for explanatory purposes.

Disclosed are components that can be used to perform the disclosed methods and systems. It is understood that when combinations, subsets, interactions, groups, etc. of these components are disclosed that while specific reference of each various individual and collective combinations and permutation of these may not be explicitly disclosed, each is specifically contemplated and described herein, for all methods and systems. This applies to all aspects of this application including, but not limited to, steps in disclosed methods. Thus, if there are a variety of additional steps that can be predefined it is understood that each of these additional steps can be predefined with any specific aspect or combination of aspects of the disclosed methods.

Implementations described herein are directed toward devices, systems and methods for guarding against contact with rotating drill rods, for example and without limitation, those used in surface, underground, oilfield, exploration, and other drilling applications. For example, one or more implementations described herein comprise a drill rod guard for drill string components. In certain aspects, implementations of the present disclosure can improve safety and efficiency over conventional drill rod guard devices. In particular, one or more implementations comprise a flexible drill rod guard configured to prevent accidental contact with the drill rod while allowing for protrusion of portions of a drill head assembly, such as a motor. In one or more aspects, during use, the drill rod guard can be configured to selectively permit unobstructed access to the drill rod. It is contemplated that the drill rod guards disclosed herein can substantially increase the safety and productivity of drill operators and other drilling personnel.

Reference will now be made to the drawings to describe various aspects of one or more implementations of the invention. It is to be understood that the drawings are diagrammatic and schematic representations of one or more implementations, and are not limiting of the present disclosure. Moreover, while various drawings are provided at a scale that is considered functional for one or more implementations, the drawings are not necessarily drawn to scale for all contemplated implementations. The drawings thus represent an exemplary scale, but no inference should be drawn from the drawings as to any required scale.

In the following description, numerous specific details are set forth in order to provide a thorough understanding described herein. It will be obvious, however, to one skilled in the art that the present disclosure may be practiced without these specific details. In other instances, well-known aspects of drilling assemblies and rotating drill rods have not been described in particular detail in order to avoid unnecessarily obscuring aspects of the disclosed implementations.

Turning now to FIGS. 1-3, an implementation of one exemplary aspect of a drill rod guard 100 for use with a drilling system 150 is illustrated. The drill rod guard 100 can be used in drilling applications such as those that utilize, for example and without limitation, percussive drills, surface drills, underground drills, and the like. In exemplary aspects, the drill rod guard 100 can be configured for use with, for example and without limitation, the StopeMate™ series, the StopeMaster™ series, the BCI-2 series, or the LM™ series drill rigs manufactured by Boart Longyear (South Jordan, Utah). However, it is contemplated that the drill rod guard 100 can be used with any type of drill rig. The drill rod guard 100 can have a longitudinal axis 101. In operation, it is contemplated that the drill rod guard 100 can be substantially axially aligned with a drilling axis 155. In exemplary aspects, the drilling system 150 can comprise a feed shell 110. The feed shell 110 can have first and second side portions 111, 113 positioned on opposing sides of the longitudinal axis 101 of the drill rod guard 100 (and, thus, on opposing sides of drilling axis 155). The feed shell 110 can be configured to receive at least a portion of a drill rod 152. It is contemplated that the feed shell 110 can have a longitudinal length relative to the drilling axis 155.

In one aspect, the drill rod guard 100 can comprise a feed shaft assembly 130. The feed shaft assembly 130 can be configured to support the feed shell 110 and can comprise at least one support element 131. In exemplary aspects, as shown in FIG. 4, at least a base portion 136 of the at least one support element 131 can be configured for engagement with the feed shell 110. Alternatively, it is contemplated that the feed shaft assembly 130 can optionally be integrally formed with the feed shell 110. Optionally, the at least one support element 131 can comprise a plurality of support elements spaced relative to the longitudinal axis 101 of the drill rod guard 100 (and, thus, spaced relative to the drilling axis 155). In exemplary aspects, each support element 131 can comprise a first side portion 132 and a second side portion 134. It is contemplated that the first side portion 132 can be positioned on an opposing side of the longitudinal axis 101 of the drill rod guard 100 (and, thus, an opposing side of the drilling axis 155) from the second side portion 134. It is further contemplated that the first side portion 132 of each support element 131 can be configured to be positioned proximate the first side portion 111 of the feed shell 110. Similarly, it is contemplated that the second side portion 134 of each support element 131 can be configured to be positioned proximate the second side portion 113 of the feed shell 110.

In another aspect, the drill rod guard 100 can comprise first and second shafts 114, 115. The first shaft 114 can be pivotally coupled to the first side portions 132 of each support element 131 of the feed shaft assembly 130, and the second shaft 115 can be pivotally coupled to the second side portions 134 of each support element 131 of the feed shaft assembly 130. In operation, the first shaft 114 can be configured for selective rotation relative to a first rotational axis 118, and the second shaft 115 can be configured for selective rotation relative to a second rotational axis 119. In exemplary aspects, it is contemplated that the first rotational axis 118 can be substantially parallel to the second rotational axis 119. In additional exemplary aspects, it is contemplated that the first rotational axis 118 and the second rotational axis 119 can be substantially parallel to the longitudinal axis 101 of the drill rod guard 100 (and, thus, substantially parallel to the drilling axis 155).

Optionally, in one aspect, the first side portion 132 of each support element 131 of the feed shaft assembly 130 can comprise a bore 133 configured to receive a portion of the first shaft 114, and the second side portion 134 of each support element 131 of the feed shaft assembly 130 can comprise a bore 135 configured to receive a portion of the second shaft 115. In this aspect, it is contemplated that the bores 133 of the at least one support element 131 can be substantially axially aligned and that the bores 135 of the at least one support element 131 can be substantially axially aligned to permit receipt of the first and second shafts 114, 115 in alignment with the first and second rotational axes 118, 119.

In a further aspect, the drill rod guard 100 can comprise a plurality of guard elements 102 that cooperate to form a protective envelope around a rotating drill rod when they are in a closed position. In exemplary aspects, the plurality of guard elements 102 can optionally be provided in the form of discrete bands or flaps. The plurality of guard elements can comprise a first set of guard elements 104 operatively coupled to the first shaft 114 and a second set of guard elements 105 operatively coupled to the second shaft 115. Optionally, it is contemplated that the first set of guard elements 104 can comprise a single guard element 104 and that the second set of guard elements 105 can comprise a single guard element 105. However, in other aspects, it is contemplated that the first set of guard elements can comprise a plurality of guard elements 104 and that the second set of guard elements can comprise a plurality of guard elements 105. In exemplary aspects, the first set of guard elements 104 can be rigidly mounted to the first shaft 114, and the second set of guard elements 105 can be rigidly mounted to the second shaft 115. Each guard element 104 of the first set of guard elements can be substantially opposed from and configured for selective engagement with a corresponding guard element 105 of the second set of guard elements.

In at least one aspect, each one of the first and second shafts 114, 115 can comprise an elongate member having a plurality of holes (e.g., threaded holes) formed along its length. It is contemplated that each hole of the plurality of holes can be configured to receive a mechanical fastener, such as, for example and without limitation, a screw, a bolt, or the like. It is further contemplated that the plurality of holes of the first shaft 114 can be configured to receive fasteners that are mounted to respective guard elements 104 of the first set of guard elements, while the plurality of holes of the second shaft 115 can be configured to receive fasteners that are mounted to respective guard elements 105 of the second set of guard elements. In exemplary aspects, the first and second shafts 114, 115 can comprise square cold rolled steel stock or the like.

In an additional aspect, the drill rod guard 100 can further comprise a plurality of bushings 140 positioned between adjacent guard elements 102 of the plurality of guard elements. It is contemplated that bushings 140 positioned between adjacent guard elements 104 of the first set of guard elements can be configured to receive a portion of the first shaft 114, while bushings 140 positioned between adjacent guard elements 105 of the second set of guard elements can be configured to receive a portion of the second shaft 115. In operation, it is contemplated that the bushings 140 can function as bearings that provide flexibility in the mounting of the guard elements 102 relative to the feed shell 110. In exemplary aspects, the bushings 140 can comprise ultra-high molecular weight (UHMW) polyethylene. However, it contemplated that any conventional rotational bushing or bearing can be used.

Upon engagement between the first set of guard elements 104 and the second set of guard elements 105, and with reference to FIG. 4, the plurality of guard elements can be configured to cooperate with the first and second side portions 111, 113 of the feed shell 110 and/or the first and second side portions 132, 134 of the feed shaft assembly 130 to substantially enclose the portion of the drill rod 152 within the feed shell.

In exemplary aspects, and with reference to FIGS. 2 and 3, the first and second shafts 114, 115 can be configured for rotation about and between a first rotational position (see FIG. 2) and a second rotational position (see FIG. 3). In these aspects, and with reference to FIGS. 2 and 6A-6C, when the first and second shafts 114, 115 are positioned in the first rotational position, each respective guard element 102 can be configured for movement about and between a closed position (see FIGS. 2 and 6A) and a partially open position (see FIGS. 6B-6C). When a guard element 102 is in the closed position, it is contemplated that the guard element can be positioned for engagement with a corresponding opposed guard element. For example, when a guard element 104 of the first set of guard elements is in the closed position, the guard element can be positioned for engagement with a corresponding opposed guard element 105 of the second set of guard elements when the opposed guard element is in its closed position. When the guard elements are positioned in the closed position, it is contemplated that a guard element 104 of the first set of guard elements can cooperate with adjacent guard elements of the first set of guard elements to define the envelope surrounding the feed shell 110. Similarly, it is contemplated that a guard element 105 of the second set of guard elements can cooperate with adjacent guard elements of the second set of guard elements to define the envelope surrounding the feed shell 110.

In further aspects, and with reference to FIG. 3, when the first and second shafts 114, 115 are positioned in the second rotational position, each respective guard element 102 can be positioned in a fully open position. In these aspects, it is contemplated that the first and second shafts 114, 115 can be moved to the second rotational position (and, thus, the guard elements 102 can be positioned in the fully open position) to permit complete access to a drill rod or other drilling system component positioned within the drill rod guard 100. In exemplary aspects, the drill rod guard 100 can comprise first and second rotary actuators 120, 121 configured to respectively effect selective rotation of the first and second shafts 114, 115 relative to the first and second rotational axes (between the first and second rotational positions).

In at least one aspect illustrated in FIGS. 4-5, each guard element 102 of the drill rod guard 100 can comprise a flexible, elastic material. In exemplary aspects, each guard element 102 can comprise polyurethane. However, it is contemplated that any flexible and elastic material capable of functioning as disclosed herein can be used.

In operation, when the first and second shafts 114, 115 are positioned in the first rotational position, each respective guard element 102 can be configured for movement to the partially open position upon application of an outward radial force to the guard element relative to the longitudinal axis 101 of the drill rod guard 100 (and, thus, relative to the drilling axis 155). After the outward radial force is removed from a guard element 102, the guard element can be configured to return to the closed position.

In exemplary aspects, each guard element 102 can be configured to permit bending of the guard element in a direction away from the longitudinal axis 101 of the drill rod guard 100 (and, thus, away from the drilling axis 155) and to limit bending of the guard element in other directions. In one aspect, each guard element 102 can have an inner surface 124 and an outer surface 128. In exemplary aspects, the inner surface 124 of each guard element 102 can define an inner shoulder surface 122. The shoulder surface 122 of each guard element 104 of the first set of guard elements can be configured to engage a portion of the first shaft 114 to limit bending of the guard element toward the longitudinal axis 101 of the drill rod guard 100 (and, thus, to limit bending of the guard element toward the drilling axis 155). Similarly, the shoulder surface 122 of each guard element 105 of the second set of guard elements can be configured to engage a portion of the second shaft 115 to limit bending of the guard element toward the longitudinal axis 101 of the drill rod guard 100 (and, thus, to limit bending of the guard element toward the drilling axis 155). It is contemplated that the flexible guard elements 102 can be configured to bend inwardly but that they are configured to effectively guard against a person falling into the drill rod guard 100 and contacting a rotating drill rod.

In a further aspect, and with reference to FIG. 4, each guard element 102 can have a proximal end 123 operatively coupled to one of the first and second shafts 114, 115 and an opposed distal end 125. In this aspect, each guard element 104 of the first set of guard elements can have a proximal end 123 operatively coupled to the first shaft 114 and an opposed distal end 125, while each guard element 105 of the second set of guard elements can have a proximal end operatively coupled to the second shaft 115 and an opposed distal end 125. In exemplary aspects, the distal end of each guard element 102 can comprise at least one engagement member 129. In these aspects, the at least one engagement member 129 of each respective guard element 104 of the first set of guard elements can be configured for complementary engagement with the at least one engagement member of a corresponding guard element 105 of the second set of guard elements. Optionally, and with reference to FIGS. 5A-5B, the at least one engagement member 129 can comprise at least one alignment finger configured to interdigitate with a corresponding at least one alignment finger of an opposing guard element. However, it is contemplated that any means for establishing selective engagement between the first and second sets of guard elements can be used. For example, it is contemplated that the means for establishing selective engagement between the first and second sets of guard elements can comprise at least one projection defined by a first guard element and configured for receipt within a receptacle defined by an opposed second guard element, frictional engagement between contacting surfaces of opposed guard elements when the guard elements are positioned in the closed position, temporary adhesion between contacting surfaces of opposed guard elements when the guard elements are positioned in the closed position, conventional mechanical fasteners, and the like.

In additional exemplary aspects, each guard element 102 of the plurality of guard elements can be biased toward the closed position. In these aspects, the drill rod guard 100 can comprise means for biasing each guard element 102 toward the closed position. It is contemplated that the means for biasing each guard element 102 toward the closed position can comprise any conventional biasing element, including, for example and without limitation, a spring-loaded biasing element or an inwardly-biased hinge. Optionally, in exemplary aspects, and with reference to FIGS. 5A-5B, the means for biasing each guard element 102 toward the closed position can comprise a groove 126 defined in the outer surface 128 of each guard element. In these aspects, the groove 126 can function as a hinge that is configured to bias the guard element toward the closed position when the first and second shafts 114, 115 are in the first rotational position.

In other exemplary aspects, at least a portion of each guard element can comprises an elastic material. It is contemplated that the hinge portion of the each guard element can comprise an elastic material. Optionally, as described above, it is contemplated that a conventional bias element, such as, for example and without limitation, a spring, a leaf spring, and the like, can be coupled to portion of each guard element proximal to the hinge to allow for the desired biasable movement of the respective guard elements relative to the respective shafts.

In exemplary aspects, the drilling system 150 can comprise a drill head assembly 112, and the drill head assembly can be operatively coupled to at least one drill rod (or drill string component) as is understood in the art. Optionally, the drill head assembly 112 can be operatively coupled to the feed shell 110 and configured for selective axial movement along the length of the feed shell relative to the drilling axis 155. In one aspect, the drill head assembly 112 can comprise a plurality of drill head components 154 and a deflecting frame 116 that generally defines an outer periphery of the drill head assembly. It is contemplated that the deflecting frame 116 can be radially spaced from the plurality of drill head components 154 as shown in FIGS. 1 and 6A-6D. Upon axial movement of the drill head assembly 112 through the drill rod guard, the deflecting frame 116 can be configured to contact the inner surfaces 124 of the plurality of guard elements 102. It is contemplated that the deflecting frame 116 can mounted or otherwise secured to one or more of the drill head components 154 (for example, by a plurality of mounting brackets) such that it is spaced from the plurality of drill head components 154 and such that the guard elements 102 do not contact the drill head components during movement of the drill head assembly 112 through the drill rod guard 100. When the guard elements 102 are positioned in the closed position, it is contemplated that the inner surfaces 124 of the opposing guard elements 104, 105 of the first and second sets of guard elements can define an operative inner diameter of the envelope formed by the drill rod guard 100. It is further contemplated that at least a front end portion 117 of the deflecting frame 116 can have an outer diameter that is less than the operative inner diameter of the drill rod guard 100 to permit entry of the drill head assembly 112 into the drill rod guard. It is still further contemplated that the operative vertical position of the deflecting frame 116 relative to the feed shell 110 can be less than an operative height of the opening defined by the drill rod guard 100 when the guard elements 102 are in the closed position. In exemplary aspects, at least a portion of the drill head components 154 of the drill head assembly 112 can protrude from the drill rod guard 100 during movement of the drill head assembly through the drill rod guard. In additional exemplary aspects, it is contemplated that the drill head assembly 112 can comprise a viewing window that is positioned to extend over at least a portion of the drill rod guard 100 during movement of the drill head assembly through the drill rod guard. It is further contemplated that the viewing window can be configured to cover at least the openings formed between opposing guard elements 102 as the deflecting frame 116 forces the guard elements into the partially open position. It is still further contemplated that the viewing window can permit a drill operator to safely view a rotating drill rod during movement of the drill head assembly 112 through the drill rod guard 100.

With reference to FIGS. 6A-6D, when the first and second shafts 114, 115 are positioned in the first rotational position and the drill head assembly 112 moves through the drill rod guard 100 relative to the drilling axis 155, each respective guard element 102 can be configured for movement to the partially open position upon application of an outward radial force to the guard element by the deflecting frame 116. It is contemplated that each respective guard element can be configured to return to the closed position when the outward radial force is removed upon disengagement between the deflecting frame and the guard element. Thus, after the deflecting frame passes a set of opposing guard elements 102, the opposing guard elements can return to the closed position.

Accordingly, FIGS. 1-6D and the corresponding text provide a number of different components and mechanisms for guarding against contact with rotating drill rods. In addition to the foregoing, implementations described herein can also be described in terms of acts and steps in a method for accomplishing a particular result. For example, a method for guarding against contact with rotating drill rods is described concurrently above with reference to the components and diagrams of FIGS. 1 through 6D.

In exemplary aspects, a method of drilling can comprise using a drilling system as disclosed herein to form a hole within a drilling formation. In additional aspects, the method of drilling can comprise selectively positioning the plurality of guard elements in a closed position during operation of the drill head assembly. In further aspects, the method can comprise selectively positioning the plurality of guard elements in an open position when the drill head assembly is not in use. In still further aspects, the method can comprise selectively advancing the drill head assembly along the feed shell relative to the drilling axis to effect movement of at least one pair of opposed guard elements to the partially open position. In these aspects, the method can comprise further advancing the drill head assembly along the feed shell relative to the drilling axis to remove contact between the deflecting frame of the drill head assembly and at least one pair of opposed guard elements to permit return of the at least one pair of opposed guard elements to the closed position.

Exemplary Aspects

In one exemplary aspect, disclosed herein is a drill rod guard for use with a drilling system, the drill rod guard having a longitudinal axis, the drilling system comprising a feed shell having first and second side portions positioned on opposing sides of the longitudinal axis of the drill rod guard, the feed shell being configured to receive at least a portion of a drill rod, the drill rod guard comprising: a feed shaft assembly configured to support the feed shell, the feed shaft assembly comprising at least one support element, wherein each support element comprises a first side portion and a second side portion, the first side portion being positioned on an opposing side of the longitudinal axis of the drill rod guard from the second side portion, wherein the first side portion of each support element is configured to be positioned proximate the first side portion of the feed shell, and wherein the second side portion of each support element is configured to be positioned proximate the second side portion of the feed shell; opposed first and second shafts, the first shaft being pivotally coupled to the first side portions of each support element of the feed shaft assembly, the second shaft being pivotally coupled to the second side portions of each support element of the feed shaft assembly, wherein the first shaft is configured for selective rotation relative to a first rotational axis and the second shaft is configured for selective rotation relative to a second rotational axis, and wherein the first rotational axis and the second rotational axis are substantially parallel to the longitudinal axis of the drill rod guard; and a plurality of guard elements, the plurality of guard elements comprising a first set of guard elements operatively coupled to the first shaft and a second set of guard elements operatively coupled to the second shaft, each guard element of the first set of guard elements being substantially opposed from and configured for selective engagement with a corresponding guard element of the second set of guard elements, wherein, upon engagement between the first set of guard elements and the second set of guard elements, the plurality of guard elements are configured to cooperate with the first and second side portions of the feed shell to substantially enclose the portion of the drill rod within the feed shell.

In other exemplary aspects, the at least one support element of the feed shaft assembly comprises a plurality of support elements spaced relative to the longitudinal axis of the drill rod guard.

In other exemplary aspects, the first side portion of each support element of the feed shaft assembly comprises a bore configured to receive a portion of the first shaft, and the second side portion of each support element of the feed shaft assembly comprises a bore configured to receive a portion of the second shaft.

In other exemplary aspects, the drill rod guard further comprises a plurality of bushings positioned between adjacent guard elements of the plurality of guard elements.

In other exemplary aspects, the first and second shafts are configured for rotation about and between a first rotational position and a second rotational position, wherein when the first and second shafts are positioned in the first rotational position, each respective guard element is configured for movement about and between a closed position and a partially open position, and wherein in the closed position, the guard element is positioned for engagement with a corresponding opposed guard element.

In other exemplary aspects, when the first and second shafts are positioned in the second rotational position, each respective guard element is positioned in a fully open position.

In other exemplary aspects, each guard element of the plurality of guard elements is biased toward the closed position.

In other exemplary aspects, the first set of guard elements is rigidly mounted to the first shaft, and the second set of guard elements is rigidly mounted to the second shaft, and each guard element comprises an outer portion that defines a hinge configured to bias the guard element toward the closed position.

In other exemplary aspects, each guard element comprises an elastic material.

In other exemplary aspects, when the first and second shafts are positioned in the first rotational position, each respective guard element is configured for movement to the partially open position upon application of an outward radial force to the guard element relative to the longitudinal axis of the drill rod guard and each respective guard element is configured to return to the closed position upon removal of the outward radial force.

In other exemplary aspects, each respective guard element defines an inner shoulder surface, wherein the inner shoulder surface of each guard element of the first set of guard elements is configured to engage a portion of the first shaft to limit bending of the guard element toward the longitudinal axis of the drill rod guard, and wherein the inner shoulder surface of each guard element of the second set of guard elements is configured to engage a portion of the second shaft to limit bending of the guard element toward the longitudinal axis of the drill rod guard.

In other exemplary aspects, each guard element has a proximal end operatively coupled to one of the first and second shafts and an opposed distal end, wherein the distal end of each guard element comprises at least one engagement member, and wherein the at least one engagement member of each respective guard element of the first set of guard elements is configured for complementary engagement with the at least one engagement member of a corresponding guard element of the second set of guard elements.

In an additional exemplary aspect, disclosed herein is a drilling system configured for drilling relative to a drilling axis, comprising: a drill head assembly; a drill rod operatively coupled to the drill head assembly; a feed shell having first and second side portions positioned on opposing sides of the drilling axis, the feed shell being configured to receive at least a portion of a drill rod; and a drill rod guard comprising: a feed shaft assembly configured to support the feed shell, the feed shaft assembly comprising at least one support element, wherein each support element comprises opposed first and second side portions, the first side portion being positioned proximate the first side portion of the feed shell and the second side portion of each support element being positioned proximate the second side portion of the feed shell; opposed first and second shafts, the first shaft being pivotally coupled to the first side portions of each support element of the feed shaft assembly, the second shaft being pivotally coupled to the second side portions of each support element of the feed shaft assembly, wherein the first shaft is configured for selective rotation relative to a first rotational axis and the second shaft is configured for selective rotation relative to a second rotational axis, and wherein the first rotational axis and the second rotational axis are substantially parallel to the drilling axis; and a plurality of guard elements, the plurality of guard elements comprising a first set of guard elements operatively coupled to the first shaft and a second set of guard elements operatively coupled to the second shaft, each guard element of the first set of guard elements being substantially opposed from and configured for selective engagement with a corresponding guard element of the second set of guard elements, wherein, upon engagement between the first set of guard elements and the second set of guard elements, the plurality of guard elements are configured to cooperate with the first and second side portions of the feed shell to substantially enclose the portion of the drill rod within the feed shell.

In other exemplary aspects, the at least one support element of the feed shaft assembly comprises a plurality of support elements spaced relative to the drilling axis.

In other exemplary aspects, the first side portion of each support element of the feed shaft assembly comprises a bore configured to receive a portion of the first shaft, and the second side portion of each support element of the feed shaft assembly comprises a bore configured to receive a portion of the second shaft.

In other exemplary aspects, the drilling system further comprises a plurality of bushings positioned between adjacent guard elements of the plurality of guard elements.

In other exemplary aspects, the first and second shafts are configured for rotation about and between a first rotational position and a second rotational position, wherein when the first and second shafts are positioned in the first rotational position, each respective guard element is configured for movement about and between a closed position and a partially open position, and wherein in the closed position, the guard element is positioned for engagement with a corresponding opposed guard element.

In other exemplary aspects, when the first and second shafts are positioned in the second rotational position, each respective guard element is positioned in a fully open position to permit access to the drill rod.

In other exemplary aspects, each guard element of the plurality of guard elements is biased toward the closed position.

In other exemplary aspects, the first set of guard elements is rigidly mounted to the first shaft, the second set of guard elements is rigidly mounted to the second shaft, and each guard element comprises an outer portion that defines a hinge configured to bias the guard element toward the closed position.

In other exemplary aspects, wherein at least a portion of each guard element comprises an elastic material. It is contemplated that the hinge portion of the each guard element can comprise an elastic material. Optionally, it is contemplated that a conventional bias element, such as, for example and without limitation, a spring, a leaf spring, and the like, can be coupled to portion of each guard element to allow for the desired biasable movement of the respective guard elements relative to the respective shafts.

In other exemplary aspects, the drill head assembly is configured for selective axial movement along a length of the feed shell relative to the drilling axis, wherein the drill head assembly comprises plurality of drill head components and a deflecting frame that generally defines an outer periphery of the drill head assembly and is spaced from the plurality of drill head components, and wherein upon axial movement of the drill head assembly through the drill rod guard, the deflecting frame is configured to contact inner surfaces of the plurality of guard elements.

In other exemplary aspects, when the first and second shafts are positioned in the first rotational position and the drill head assembly moves through the drill rod guard relative to the drilling axis, each respective guard element is configured for movement to the partially open position upon application of an outward radial force to the guard element by the deflecting frame of the drill head assembly and each respective guard element is configured to return to the closed position when the outward radial force is removed upon disengagement between the deflecting frame and the guard element.

In other exemplary aspects, each respective guard element defines an inner shoulder surface, wherein the inner shoulder surface of each guard element of the first set of guard elements is configured to engage a portion of the first shaft to limit bending of the guard element toward the drilling axis, and wherein the inner shoulder surface of each guard element of the second set of guard elements is configured to engage a portion of the second shaft to limit bending of the guard element toward the drilling axis.

In other exemplary aspects, each guard element has a proximal end operatively coupled to one of the first and second shafts and an opposed distal end, wherein the distal end of each guard element comprises at least one engagement member, and wherein the at least one engagement member of each respective guard element of the first set of guard elements is configured for complementary engagement with the at least one engagement member of a corresponding guard element of the second set of guard elements.

In a further exemplary aspect, disclosed herein is a method of drilling comprising using a drilling system as described herein to form a hole within a formation. In other exemplary aspects, the method of drilling can further comprise selectively positioning the plurality of guard elements in a closed position during operation of the drill head assembly. In other exemplary aspects, the method of drilling can further comprise selectively positioning the plurality of guard elements in an open position when the drill head assembly is not in use.

The present invention can thus be embodied in other specific forms without departing from its spirit or essential characteristics. The described aspects are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope. 

1. A drill rod guard for use with a drilling system, the drill rod guard having a longitudinal axis, the drilling system comprising a feed shell having first and second side portions positioned on opposing sides of the longitudinal axis of the drill rod guard, the feed shell being configured to receive at least a portion of a drill rod, the drill rod guard comprising: a feed shaft assembly configured to support the feed shell, the feed shaft assembly comprising at least one support element, wherein each support element comprises a first side portion and a second side portion, the first side portion being positioned on an opposing side of the longitudinal axis of the drill rod guard from the second side portion, wherein the first side portion of each support element is configured to be positioned proximate the first side portion of the feed shell, and wherein the second side portion of each support element is configured to be positioned proximate the second side portion of the feed shell; opposed first and second shafts, the first shaft being pivotally coupled to the first side portions of each support element of the feed shaft assembly, the second shaft being pivotally coupled to the second side portions of each support element of the feed shaft assembly, wherein the first shaft is configured for selective rotation relative to a first rotational axis and the second shaft is configured for selective rotation relative to a second rotational axis, and wherein the first rotational axis and the second rotational axis are substantially parallel to the longitudinal axis of the drill rod guard; and a plurality of guard elements, the plurality of guard elements comprising a first set of guard elements operatively coupled to the first shaft and a second set of guard elements operatively coupled to the second shaft, each guard element of the first set of guard elements being substantially opposed from and configured for selective engagement with a corresponding guard element of the second set of guard elements, wherein, upon engagement between the first set of guard elements and the second set of guard elements, the plurality of guard elements are configured to cooperate with the first and second side portions of the feed shell to substantially enclose the portion of the drill rod within the feed shell.
 2. The drill rod guard of claim 1, wherein the at least one support element of the feed shaft assembly comprises a plurality of support elements spaced relative to the longitudinal axis of the drill rod guard.
 3. The drill rod guard of claim 1, wherein the first side portion of each support element of the feed shaft assembly comprises a bore configured to receive a portion of the first shaft, and wherein the second side portion of each support element of the feed shaft assembly comprises a bore configured to receive a portion of the second shaft.
 4. The drill rod guard of claim 1, further comprising a plurality of bushings positioned between adjacent guard elements of the plurality of guard elements.
 5. The drill rod guard of claim 1, wherein the first and second shafts are configured for rotation about and between a first rotational position and a second rotational position, wherein when the first and second shafts are positioned in the first rotational position, each respective guard element is configured for movement about and between a closed position and a partially open position, wherein in the closed position, the guard element is positioned for engagement with a corresponding opposed guard element.
 6. The drill rod guard of claim 5, wherein when the first and second shafts are positioned in the second rotational position, each respective guard element is positioned in a fully open position.
 7. The drill rod guard of claim 5, wherein each guard element of the plurality of guard elements is biased toward the closed position.
 8. The drill rod guard of claim 7, wherein the first set of guard elements is rigidly mounted to the first shaft, and wherein the second set of guard elements is rigidly mounted to the second shaft, and wherein each guard element comprises an outer portion that defines a hinge configured to bias the guard element toward the closed position.
 9. The drill rod guard of claim 8, wherein at least a portion of each guard element comprises an elastic material.
 10. The drill rod guard of claim 9, wherein when the first and second shafts are positioned in the first rotational position, each respective guard element is configured for movement to the partially open position upon application of an outward radial force to the guard element relative to the longitudinal axis of the drill rod guard and each respective guard element is configured to return to the closed position upon removal of the outward radial force.
 11. The drill rod guard of claim 8, wherein each respective guard element defines an inner shoulder surface, wherein the inner shoulder surface of each guard element of the first set of guard elements is configured to engage a portion of the first shaft to limit bending of the guard element toward the longitudinal axis of the drill rod guard, and wherein the inner shoulder surface of each guard element of the second set of guard elements is configured to engage a portion of the second shaft to limit bending of the guard element toward the longitudinal axis of the drill rod guard.
 12. The drill rod guard of claim 1, wherein each guard element has a proximal end operatively coupled to one of the first and second shafts and an opposed distal end, wherein the distal end of each guard element comprises at least one engagement member, and wherein the at least one engagement member of each respective guard element of the first set of guard elements is configured for complementary engagement with the at least one engagement member of a corresponding guard element of the second set of guard elements.
 13. A drilling system configured for drilling relative to a drilling axis, comprising: a drill head assembly; a drill rod operatively coupled to the drill head assembly; a feed shell having first and second side portions positioned on opposing sides of the drilling axis, the feed shell being configured to receive at least a portion of a drill rod; and a drill rod guard comprising: a feed shaft assembly configured to support the feed shell, the feed shaft assembly comprising at least one support element, wherein each support element comprises opposed first and second side portions, the first side portion being positioned proximate the first side portion of the feed shell and the second side portion of each support element being positioned proximate the second side portion of the feed shell; opposed first and second shafts, the first shaft being pivotally coupled to the first side portions of each support element of the feed shaft assembly, the second shaft being pivotally coupled to the second side portions of each support element of the feed shaft assembly, wherein the first shaft is configured for selective rotation relative to a first rotational axis and the second shaft is configured for selective rotation relative to a second rotational axis, and wherein the first rotational axis and the second rotational axis are substantially parallel to the drilling axis; and a plurality of guard elements, the plurality of guard elements comprising a first set of guard elements operatively coupled to the first shaft and a second set of guard elements operatively coupled to the second shaft, each guard element of the first set of guard elements being substantially opposed from and configured for selective engagement with a corresponding guard element of the second set of guard elements, wherein, upon engagement between the first set of guard elements and the second set of guard elements, the plurality of guard elements are configured to cooperate with the first and second side portions of the feed shell to substantially enclose the portion of the drill rod within the feed shell.
 14. The drilling system of claim 13, wherein the at least one support element of the feed shaft assembly comprises a plurality of support elements spaced relative to the drilling axis.
 15. The drilling system of claim 13, wherein the first side portion of each support element of the feed shaft assembly comprises a bore configured to receive a portion of the first shaft, and wherein the second side portion of each support element of the feed shaft assembly comprises a bore configured to receive a portion of the second shaft.
 16. The drilling system of claim 13, further comprising a plurality of bushings positioned between adjacent guard elements of the plurality of guard elements.
 17. The drilling system of claim 13, wherein the first and second shafts are configured for rotation about and between a first rotational position and a second rotational position, wherein when the first and second shafts are positioned in the first rotational position, each respective guard element is configured for movement about and between a closed position and a partially open position, wherein in the closed position, the guard element is positioned for engagement with a corresponding opposed guard element.
 18. The drilling system of claim 17, wherein when the first and second shafts are positioned in the second rotational position, each respective guard element is positioned in a fully open position to permit access to the drill rod.
 19. The drilling system of claim 17, wherein each guard element of the plurality of guard elements is biased toward the closed position.
 20. The drilling system of claim 19, wherein the first set of guard elements is rigidly mounted to the first shaft, wherein the second set of guard elements is rigidly mounted to the second shaft, and wherein each guard element comprises an outer portion that defines a hinge configured to bias the guard element toward the closed position.
 21. The drilling system of claim 20, wherein at least a portion of each guard element comprises an elastic material.
 22. The drilling system of claim 19, wherein the drill head assembly is configured for selective axial movement along a length of the feed shell relative to the drilling axis, wherein the drill head assembly comprises plurality of drill head components and a deflecting frame that generally defines an outer periphery of the drill head assembly and is spaced from the plurality of drill head components, wherein upon axial movement of the drill head assembly through the drill rod guard, the deflecting frame is configured to contact inner surfaces of the plurality of guard elements.
 23. The drilling system of claim 22, wherein when the first and second shafts are positioned in the first rotational position and the drill head assembly moves through the drill rod guard relative to the drilling axis, each respective guard element is configured for movement to the partially open position upon application of an outward radial force to the guard element by the deflecting frame of the drill head assembly and each respective guard element is configured to return to the closed position when the outward radial force is removed upon disengagement between the deflecting frame and the guard element.
 24. The drilling system of claim 20, wherein each respective guard element defines an inner shoulder surface, wherein the inner shoulder surface of each guard element of the first set of guard elements is configured to engage a portion of the first shaft to limit bending of the guard element toward the drilling axis, and wherein the inner shoulder surface of each guard element of the second set of guard elements is configured to engage a portion of the second shaft to limit bending of the guard element toward the drilling axis.
 25. The drilling system of claim 13, wherein each guard element has a proximal end operatively coupled to one of the first and second shafts and an opposed distal end, wherein the distal end of each guard element comprises at least one engagement member, and wherein the at least one engagement member of each respective guard element of the first set of guard elements is configured for complementary engagement with the at least one engagement member of a corresponding guard element of the second set of guard elements.
 26. A method of drilling relative to a drilling axis, comprising: operatively coupling a drill rod to a drill head assembly; positioning at least a portion of the drill rod within a feed shell, the feed shell having first and second side portions positioned on opposing sides of the drilling axis; and using a drill rod guard to substantially enclose the portion of the drill rod within the feed shell, the drill rod guard comprising: a feed shaft assembly configured to support the feed shell, the feed shaft assembly comprising at least one support element, wherein each support element comprises opposed first and second side portions, the first side portion being positioned proximate the first side portion of the feed shell and the second side portion of each support element being positioned proximate the second side portion of the feed shell; opposed first and second shafts, the first shaft being pivotally coupled to the first side portions of each support element of the feed shaft assembly, the second shaft being pivotally coupled to the second side portions of each support element of the feed shaft assembly, wherein the first shaft is configured for selective rotation relative to a first rotational axis and the second shaft is configured for selective rotation relative to a second rotational axis, and wherein the first rotational axis and the second rotational axis are substantially parallel to the drilling axis; and a plurality of guard elements, the plurality of guard elements comprising a first set of guard elements operatively coupled to the first shaft and a second set of guard elements operatively coupled to the second shaft, each guard element of the first set of guard elements being substantially opposed from and configured for selective engagement with a corresponding guard element of the second set of guard elements, wherein, upon engagement between the first set of guard elements and the second set of guard elements, the plurality of guard elements cooperate with the first and second side portions of the feed shell to substantially enclose the portion of the drill rod within the feed shell.
 27. (canceled)
 28. The method of claim 26, further comprising: selectively positioning the plurality of guard elements in an open position when the drill head assembly is not in use, wherein in the open position the first set of guard elements is disengaged from the second set of guard elements.
 29. The drilling method of claim 26, wherein the at least one support element of the feed shaft assembly of the drill rod guard comprises a plurality of support elements spaced relative to the drilling axis. 